1. Field of the Disclosure
The present disclosure relates to an electronic device formed by placing a substrate provided with electronic components in a housing and suitable for application to a cellular phone, a PHS (Personal Handyphone System) phone, a PDA (Personal Digital Assistant) device, a digital camera device, a digital video camera device, a portable gaming device, and a notebook personal computer device, for example, and relates to a method of radiating heat from an electronic device. In particular, the present disclosure relates to an electronic device and a method of radiating heat from an electronic device that allows for strong radiation of heat generated from electronic devices housed in a housing to the outside of the housing.
2. Description of Related Art
Japanese Unexamined Patent Application Publication No. 2008-53790 describes a folding cellular phone intended to efficiently radiate heat generated from heat generating elements mounted on a substrate to the outside.
The folding cellular phone is formed by an upper body including a display section, a lower body including a key operation section, and a hinge mechanism that rotatably couples the upper body and the lower body to each other.
The lower body includes a shield case formed by a metal member, an IC card holder that is formed by a metal member and that can receive an IC card for connection, and a control substrate having heat generating elements. The hinge mechanism includes first to third frames formed by a metal member.
In the folding cellular phone, the shield case and the IC card holder of the lower body abut against each other via the first frame of the hinge mechanism, and a power amplifier, which is a main heat generating element of the control substrate, contacts the shield case.
This allows heat generated from the heat generating elements such as the power amplifier mounted on the substrate to be transmitted sequentially through internal components of the cellular phone via a metal member with high heat conductivity and to be radiated from all the internal components made of a metal material.
This is also the case with other types of cellular phones. FIG. 10 is a perspective view of a main portion of a cellular phone formed in a generally rectangular plate shape and provided with a large display section.
This cellular phone includes a center panel 100 formed in a rectangular plate shape as shown in FIG. 10. The center panel 100 serves as the framework of the cellular phone, and is formed by a high-strength metal plate such as a stainless steel member and a high-strength resin such as an ABS resin, a polycarbonate resin, or the like, for example.
Electronic components such as a central processing unit (CPU), a memory, a communication circuit (such as an RF module), a power amplifier, a speaker section, a camera section, and a display section are provided on the center panel 100, either directly or via a circuit substrate.
The outer peripheral portion along the four sides of the center panel 100 is fixed to an outer frame member 101 formed by a high-strength resin such as an ABS resin, a polycarbonate resin, or the like, for example. The upper housing and the lower housing are fixed to the outer frame member 101 so as to sandwich the outer frame member 101 vertically. This allows the center panel 100 to be housed in the housing of the cellular phone while being surrounded by the outer frame member 101.
In the cellular phone, electronic components serving as heat sources such as a CPU and a power amplifier, for example, are provided in the vicinity of the upper end portion indicated by a dotted circle in FIG. 10, for example. Therefore, a portion of the center panel 100 in the vicinity of the upper end portion is formed by providing a high-strength metal plate such as a stainless steel member 100a, for example, and applying a high-heat conductivity member such as a copper plate 102 onto the stainless steel member 100a. 
In the cellular phone, heat generated from the electronic components serving as heat sources is absorbed and diffused by the high-heat conductivity member such as the copper plate 102.